As known to all, the traditional control manner of mechanical arm systems is a manual mode of manual operation, and an operator operates different handles to realize coordinated movements of multiple segments of a mechanical arm and then to reach a target position, but this manner has many disadvantages. For example, during the manual operation, especially in a situation of desiring the linkage and coordination of multiple segments of the mechanical arm, the efficiency and precision of the manual operation are usually low; the manual operation has high requirement on the operator's proficiency in the operation, and during the operation, the operator needs to always take care of the movements of the articulated arm, and there exists the danger of throwing construction personnel off buildings in case of any carelessness, thus there exists the disadvantages of poor safety and high labour strength.
With the quickly changing developments of society and science, how to provide a better working environment for workers and how to reduce the labour strength of the workers to the maximum extent have been always a focus and a hot issue during the research and development of mechanical arm systems. In 1993, the PUTZMEISTER company put forward in the U.S. Pat. No. 5,640,996A realizing the coordinated movements of multiple segments of a mechanical arm by the separate adjustment of the handles of a remote controller, so that the multiple segments will not affect one another and can independently retract, rotate and elevate, and also disclosed the first time in 1994 in the U.S. Pat. No. 5,823,218 the follow-up function of an end hose, that is, an operator guides the end hose to move to a concrete pouring point to realize the follow-up function of the mechanical arm.
Although research personnel home and abroad have always been trying to realize the robotization of mechanical arms, up to now, the application still cannot fully meet the demand of engineering, and the difficulty mainly lies in the precision of control.
Referring to FIG. 1, it is a schematic diagram of a two-segment articulated arm, from FIG. 1 the two-axle mechanical arm can rotate about the joints O1 and O2, and the length of O1 and O2 is 11, the length of O2 A is 12, from geometric analysis and according to the rotation angles θ1 and θ2 of the joints, the movement equation of the mechanical arm can be established as follow:x=l1 cos θ1+l2 cos(θ1+θ2)  Equation 1y=l1 sin θ1+l2 sin(θ1+θ2)  Equation 2,wherein, (x, y) are the coordinate of the tail end A.
Further, during mechanical arm control and track planning, usually the movement amounts of the joints need to be calculated in the situation that the spatial position which a point will reach is known, so as to drive the movements of the joints and meet the position of the end point.
Equations 1 and 2 are simplified to render:x2+y2=l12+l22+2l1l2[cos θ1 cos(θ1+θ2)+sin θ1 sin(θ1+θ2)]=l12+l22+2l1l2 cos θ2   Equation 3
                              θ          2                =                  arc          ⁢                                          ⁢                      cos            (                                                            x                  2                                +                                  y                  2                                -                                  l                  1                  2                                -                                  l                  2                  2                                                            2                ⁢                                  l                  1                                ⁢                                  l                  2                                                      )                                              Formula        ⁢                                  ⁢        4                                          θ          1                =                              arc            ⁢                                                  ⁢                          tan              ⁡                              (                                  y                  x                                )                                              -                      arc            ⁢                                                  ⁢                                          cos                (                                                                            x                      2                                        +                                          y                      2                                        +                                          l                      1                      2                                        -                                          l                      2                      2                                                                            2                    ⁢                                          l                      1                                        ⁢                                                                                            x                          2                                                +                                                  y                          2                                                                                                                    )                            .                                                          Formula        ⁢                                  ⁢        5            
Thus, in the situation that the position A(X, Y) to be reached is known, the desired rotation angles θ1 and θ2 of the joints can be obtained, and driving hydraulic oil cylinder controls the rotation of the mechanical arm so that the tail end of the mechanical arm reaches the target position A(X, Y). However, the movements of the mechanical arm can be divided into rigid movement and flexible movement due to its flexibility, the above calculations omit the flexibility of the mechanical frame, which will result in that there exists great deviation between the final calculations, the planning results and the facts, thus the precision of the control is affected.